# NTSB investigations, KS: Maneuvering

NTSB aviation accident and incident investigations since 1962: the probable cause, findings, aircraft, crew, weather and docket of each, linked to the FAA registry and the FAA’s own reports.

Page 1 of 7 · 315 cases

## Latest cases

- [NTSB CEN26LA252](https://openairdocs.org/ntsb/CEN26LA252.md): Air Tractor AT802 · Whiting, KS · Accident · Minor injuries · Class 4 · Limited · Final report · Jul 13, 2026 · N808HB · Substantial damage
  > The pilot's failure to maintain clearance from an antenna while maneuvering during a low-level aerial application flight.
- [NTSB CEN25FA339](https://openairdocs.org/ntsb/CEN25FA339.md): Rans S-12 Airaile · Concordia, KS · Accident · 1 fatal · Class 3 · Field · Preliminary report · Aug 25, 2025 · N2757A · Substantial damage
  > On August 24, 2025, about 1926 central daylight time, a Rans S-12 Airaile airplane, N2757A, was substantially damaged when it was involved in an accident near Concordia, Kansas. The pilot was fatally injured. The airplane was operated as a Title 14 Code of…
- [NTSB CEN24FA248](https://openairdocs.org/ntsb/CEN24FA248.md): Rotorway Scorpion 133 · Andale, KS · Accident · 1 fatal · Class 3 · Field · Final report · Jul 5, 2024 · N51017 · Destroyed
  > The pilot’s abrupt control inputs, which resulted in a low-G condition, main rotor mast bumping, and subsequent severing of the tailboom by the main rotor blades.
- [NTSB CEN24LA193](https://openairdocs.org/ntsb/CEN24LA193.md): Air Tractor AT-502 · Covert, KS · Accident · No injuries · Class 3 · Limited · Final report · May 19, 2024 · N15189 · Substantial damage
  > The improper maintenance of the fuel control unit, which resulted in air leakage and a loss of control of fuel flow to the engine.
- [NTSB CEN24LA031](https://openairdocs.org/ntsb/CEN24LA031.md): Powrachute Pegasus · Manhattan, KS · Accident · Serious injuries · Class 3 · Limited · Final report · Oct 21, 2023 · N52631 · Substantial damage
  > The pilot’s improper modification of the engine cooling system that resulted in an engine overheat and total loss of power. Contributing to the accident was the pilot’s decision to continue the flight after the engine overheat light illuminated instead of…
- [NTSB CEN23LA308](https://openairdocs.org/ntsb/CEN23LA308.md): Hughes 369D · Atchison, KS · Accident · No injuries · Class 4 · Limited · Final report · Jul 13, 2023 · N533DR · Substantial damage
  > The pilot’s failure to adequately survey a field for obstructions prior to a low-level aerial application pass, which resulted in an impact with a powerline.
- [NTSB CEN23LA279](https://openairdocs.org/ntsb/CEN23LA279.md): Bell 206B · Chapman, KS · Accident · No injuries · Class 4 · Limited · Final report · Jul 5, 2023 · N67FA · Substantial damage
  > The pilot’s failure to maintain clearance from the power line during an agricultural application pass.
- [NTSB CEN23LA303](https://openairdocs.org/ntsb/CEN23LA303.md): Ayres S2R-G6 · Ulysses, KS · Accident · No injuries · Class 4 · Limited · Final report · May 27, 2023 · N4182G · Substantial damage
  > The pilot’s failure to maintain clearance from a cable during spray operations.
- [NTSB CEN23LA149](https://openairdocs.org/ntsb/CEN23LA149.md): Cessna 182Q · Gardner, KS · Accident · No injuries · Class 3 · Limited · Final report · Apr 7, 2023 · N982NC · Substantial damage
  > A total loss of engine power due to failure of the No. 6 connecting rod as a result of detonation.
- [NTSB CEN22LA158](https://openairdocs.org/ntsb/CEN22LA158.md): Robinson Helicopter R22 Beta · Garnett, KS · Accident · No injuries · Class 4 · Limited · Final report · Mar 26, 2022 · N7087X · Substantial damage
  > The pilot’s failure to maintain lateral control while hovering which resulted in a dynamic rollover.
- [NTSB CEN21LA362](https://openairdocs.org/ntsb/CEN21LA362.md): Air Tractor AT-502B · Topeka, KS · Accident · No injuries · Class 4 · Limited · Final report · Aug 6, 2021 · N502CP · Substantial damage
  > The pilot’s decision to continue low-level aerial application flight maneuvers after the low fuel warning light illuminated, which resulted in a partial loss of engine power due to fuel exhaustion.
- [NTSB CEN21LA286](https://openairdocs.org/ntsb/CEN21LA286.md): Ayres S2R-T34 · Leoti, KS · Accident · Minor injuries · Class 3 · Limited · Final report · Jun 21, 2021 · N4328P · Substantial damage
  > The pilot’s loss of visibility in the cockpit due to foam created by the chemicals loaded in the hopper, which resulted in his inability to maintain airplane control during low-level flight and an impact with terrain. Contributing to the accident was the…
- [NTSB CEN21LA225](https://openairdocs.org/ntsb/CEN21LA225.md): Bell OH58A · Ulysses, KS · Accident · 1 fatal · Class 3 · Limited · Final report · May 18, 2021 · N176SJ · Destroyed
  > The pilot’s failure to maintain clearance from a power line during the aerial application flight, which resulted in collision with the power line and subsequent impact with terrain.
- [NTSB CEN21LA165](https://openairdocs.org/ntsb/CEN21LA165.md): Hughes 369D · Lake City, KS · Accident · No injuries · Class 4 · Limited · Final report · Mar 25, 2021 · N41AJ · Substantial damage
  > The pilot’s failure to maintain clearance from power lines during power line maintenance.
- [NTSB CEN21LA062](https://openairdocs.org/ntsb/CEN21LA062.md): Cessna 120 · Johnson City, KS · Accident · No injuries · Class 4 · Limited · Final report · Nov 17, 2020 · N2376N · Substantial damage
  > The pilot’s improper decision to fly the airplane at too low an altitude resulting in the airplane impacting terrain.
- [NTSB CEN20CA334](https://openairdocs.org/ntsb/CEN20CA334.md): Hughes 369 · Delia, KS · Accident · No injuries · Class 4 · Data collection · Final report · Aug 5, 2020 · N104SU · Substantial damage
  > Foreign object damage sustained to the main rotor blades due to aerial tree trimming.
- [NTSB CEN19FA278](https://openairdocs.org/ntsb/CEN19FA278.md): Grumman G164 · Hays, KS · Accident · 1 fatal · Field investigation · Final report · Aug 20, 2019 · N3631Z · Destroyed
  > The pilot's exceedance of the airplane's critical angle of attack, which resulted in an aerodynamic stall.
- [NTSB GAA19CA352](https://openairdocs.org/ntsb/GAA19CA352.md): Air Tractor AT402 · Liberal, KS · Accident · No injuries · Data collection · Final report · Jun 17, 2019 · N5044Y · Substantial damage
  > The pilot's failure to see and avoid a windmill tower while maneuvering at low altitude.
- [NTSB GAA19CA328](https://openairdocs.org/ntsb/GAA19CA328.md): Air Tractor AT502 · Monument, KS · Accident · Minor injuries · Data collection · Final report · Jun 7, 2019 · N60642 · Substantial damage
  > The pilot's failure to maintain altitude due to distraction by ground equipment in the airplane’s path, which resulted in his failure to maintain clearance from crops during an agricultural application flight and resulted in a loss of airplane control.
- [NTSB GAA18CA573](https://openairdocs.org/ntsb/GAA18CA573.md): Hiller UH 12E · Frankfort, KS · Accident · No injuries · Data collection · Final report · Sep 20, 2018 · N1349A · Substantial damage
  > The ground crewmember's improper grabbing of the hovering helicopter's skid during an external load hook-up, which resulted in the helicopter descending and the main rotors striking ground equipment.
- [NTSB CEN18LA342](https://openairdocs.org/ntsb/CEN18LA342.md): Cessna A188 · Whitewater, KS · Accident · No injuries · Limited investigation · Final report · Aug 17, 2018 · N9076R · Substantial damage
  > The partial loss of engine power due to low cylinder compression, which led to the forced landing following a pull-up maneuver. Contributing to the accident was the airplane’s high gross weight.
- [NTSB CEN17LA372](https://openairdocs.org/ntsb/CEN17LA372.md): Piper PA 25-235 · Westphalia, KS · Accident · No injuries · Limited investigation · Final report · Sep 28, 2017 · N7336Z · Substantial damage
  > A total loss of engine power due to a fatigue failure of the crankshaft that resulted from main bearing shift and lack of lubrication.
- [NTSB CEN17FA270](https://openairdocs.org/ntsb/CEN17FA270.md): North American/Aero Classics P 51 · Cummings, KS · Accident · 2 fatal · Field investigation · Final report · Jul 16, 2017 · N251PW · Destroyed
  > The loss of airplane control while maneuvering at low altitude for reasons that could not be determined.
- [NTSB CEN17LA176](https://openairdocs.org/ntsb/CEN17LA176.md): Thrush S2R-H80 · Gypsum, KS · Accident · No injuries · Limited investigation · Final report · May 5, 2017 · N3045R · Substantial damage
  > A total loss of engine power during a low-altitude agricultural application flight for reasons that could not be determined during detailed examinations. Contributing to the accident was the pilot’s failure to follow the airplane manufacturer's emergency…
- [NTSB CEN17LA163](https://openairdocs.org/ntsb/CEN17LA163.md): Grumman Schweizer G-164 · Palmer, KS · Accident · No injuries · Limited investigation · Final report · Apr 17, 2017 · N9533 · Substantial damage
  > A crack in the cylinder of the radial engine, which resulted in a loss of engine power and a forced landing on unsuitable terrain.
- [NTSB CEN16LA334](https://openairdocs.org/ntsb/CEN16LA334.md): Piper PA 25-235 · Bushton, KS · Accident · Serious injuries · Limited investigation · Final report · Aug 25, 2016 · N4963Y · Substantial damage
  > A partial loss of engine power for reasons that could not be determined based on the available information.
- [NTSB CEN16CA277](https://openairdocs.org/ntsb/CEN16CA277.md): Grumman Acft ENG Cor-Schweizer G 164A · Topeka, KS · Accident · No injuries · Data collection · Final report · Jul 21, 2016 · N7997 · Substantial damage
  > The pilot’s failure to maintain clearance from a wire during an agricultural flight.
- [NTSB CEN16LA266](https://openairdocs.org/ntsb/CEN16LA266.md): Toevs Titanium Explorer · Whitewater, KS · Accident · 1 fatal · Limited investigation · Final report · Jul 16, 2016 · N556XT · Destroyed
  > The loss of aircraft control for reasons that could not be determined because postaccident examination did not reveal any anomalies that would have precluded normal operation.
- [NTSB CEN15LA330](https://openairdocs.org/ntsb/CEN15LA330.md): Grumman G-164A · Emmett, KS · Accident · Minor injuries · Limited investigation · Final report · Jul 31, 2015 · N963X · Substantial damage
  > The engine failure due to several loose, damaged cylinder stud nuts and hold-down bolts. Contributing to the accident was maintenance personnel’s failure to detect that the cylinder nuts and hold-down bolts were not properly secured during the engine’s most…
- [NTSB CEN15FA240](https://openairdocs.org/ntsb/CEN15FA240.md): Yakovlev YAK 52 · Syracuse, KS · Accident · 1 fatal · Field investigation · Final report · May 25, 2015 · N124FS · Substantial damage
  > The pilot’s failure to maintain airplane control while maneuvering at low altitude, which resulted in the airplane’s wing exceeding its critical angle-of-attack and a subsequent aerodynamic stall.
- [NTSB CEN15LA107](https://openairdocs.org/ntsb/CEN15LA107.md): Cessna 210J · Dodge City, KS · Accident · Serious injuries · Limited investigation · Final report · Jan 14, 2015 · N3320S · Substantial damage
  > The loss of engine power on approach due to fuel exhaustion, which resulted from the pilot's improper preflight fuel planning and inspection.
- [NTSB CEN14FA288](https://openairdocs.org/ntsb/CEN14FA288.md): Schrieber Robert L P 70 · Great Bend, KS · Accident · 2 fatal · Field investigation · Final report · Jun 8, 2014 · N567CM · Substantial damage
  > The pilot's improper preflight planning, which led to a loss of engine power due to fuel exhaustion. Contributing to the accident was the pilot's loss of airplane control during the forced landing.
- [NTSB CEN14LA211](https://openairdocs.org/ntsb/CEN14LA211.md): Air Tractor AT 502B · Garfield, KS · Accident · 1 fatal · Limited investigation · Final report · Apr 22, 2014 · N51990 · Substantial damage
  > The pilot’s inadequate preflight planning and subsequent failure to remain clear of power lines while maneuvering low to the ground.
- [NTSB CEN13LA439](https://openairdocs.org/ntsb/CEN13LA439.md): Woods Rufus III Vans RV-8A · Lucas, KS · Accident · 1 fatal · Limited investigation · Final report · Jul 28, 2013 · N131RP · Destroyed
  > The noninstrument-rated pilot's inadvertent entry into instrument meteorological conditions, which resulted in his spatial disorientation and a subsequent loss of airplane control.
- [NTSB CEN13LA346](https://openairdocs.org/ntsb/CEN13LA346.md): Rogers T-51 Mustang KIT · St Francis, KS · Accident · No injuries · Limited investigation · Final report · Jun 11, 2013 · N548RR · Substantial damage
  > Foreign debris in the propeller governor, which led to excessive wear in the governor and its subsequent in-flight failure.
- [NTSB CEN13LA265](https://openairdocs.org/ntsb/CEN13LA265.md): Air Tractor AT-301 · Lyons, KS · Accident · No injuries · Limited investigation · Final report · May 8, 2013 · N23257 · Substantial damage
  > The pilot's diverted attention after the door hinge failed and a piece of door glass struck the pilot, resulting in the airplane's descent into the crops and impact with terrain.
- [NTSB CEN13LA260](https://openairdocs.org/ntsb/CEN13LA260.md): Cessna A188B · Lyons, KS · Accident · Minor injuries · Limited investigation · Final report · May 7, 2013 · N731JF · Substantial damage
  > The partial loss of engine power due to fuel contamination, which resulted in impact with terrain. Contributing to the accident was the pilot's inadequate preflight inspection, during which he failed to detect the fuel contamination.
- [NTSB CEN13LA263](https://openairdocs.org/ntsb/CEN13LA263.md): Air Tractor AT-602 · Udall, KS · Accident · No injuries · Limited investigation · Final report · May 5, 2013 · N628JP · Substantial damage
  > The pilot's inadequate flight planning, which resulted in a wire strike.
- [NTSB CEN12LA552](https://openairdocs.org/ntsb/CEN12LA552.md): Cessna A150L · Tribune, KS · Accident · Serious injuries · Limited investigation · Final report · Aug 17, 2012 · N6006J · Substantial damage
  > The pilot's failure to maintain clearance from a corn crop.
- [NTSB CEN12FA521](https://openairdocs.org/ntsb/CEN12FA521.md): Ayres S2R-T34 · Lakin, KS · Accident · No injuries · Field investigation · Final report · Aug 6, 2012 · N365SM · Substantial damage
  > The pilot's failure to maintain clearance from the corn during an aerial application flight.
- [NTSB CEN12LA549](https://openairdocs.org/ntsb/CEN12LA549.md): Cessna 182D · Rose Hill, KS · Accident · No injuries · Limited investigation · Final report · Jul 28, 2012 · N8882X · Substantial damage
  > The inadvertent deployment of a skydiver's parachute, which struck the right horizontal stabilizer.
- [NTSB CEN12LA267](https://openairdocs.org/ntsb/CEN12LA267.md): Bell 206B · Valley Falls, KS · Accident · Minor injuries · Limited investigation · Final report · May 2, 2012 · N85RB · Substantial damage
  > The pilot’s inadequate compensation for the wind conditions during a hover maneuver, which resulted in a loss of tail rotor effectiveness.
- [NTSB CEN12LA236](https://openairdocs.org/ntsb/CEN12LA236.md): Ayres S2R-T15 · Lakin, KS · Accident · Serious injuries · Limited investigation · Final report · Apr 9, 2012 · N64DX · Substantial damage
  > The pilot did not maintain sufficient airspeed while maneuvering, which resulted in an aerodynamic stall at a low altitude.
- [NTSB CEN12LA135](https://openairdocs.org/ntsb/CEN12LA135.md): Cessna 150M · El Dorado, KS · Accident · No injuries · Limited investigation · Final report · Jan 13, 2012 · N714BS · Substantial damage
  > The loss of engine power for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation.
- [NTSB CEN11CA551](https://openairdocs.org/ntsb/CEN11CA551.md): Quicksilver Sprint II · Douglas, KS · Accident · Serious injuries · Data collection · Final report · Aug 6, 2011 · N403BP · Substantial damage
  > The pilot’s improper fuel management, which resulted in a loss of engine power due to fuel exhaustion.
- [NTSB CEN11LA012](https://openairdocs.org/ntsb/CEN11LA012.md): Newmann Edward W Challenger II · Easton, KS · Accident · 1 fatal · Limited investigation · Final report · Oct 8, 2010 · N61328 · Substantial damage
  > The pilot’s failure to maintain control of the airplane for undetermined reasons.
- [NTSB CEN10CA286](https://openairdocs.org/ntsb/CEN10CA286.md): Cessna 150M · Glasco, KS · Accident · Minor injuries · Data collection · Final report · May 31, 2010 · N9388U · Substantial damage
  > The pilot’s delay in applying full power to arrest a sink rate at low altitude.
- [NTSB CEN10LA099](https://openairdocs.org/ntsb/CEN10LA099.md): Buckeye DM · Sublette, KS · Accident · 2 fatal · Limited investigation · Final report · Jan 17, 2010 · N582DW · 2 aircraft · Substantial damage
  > The failure of both pilots to see and avoid the other aircraft, which resulted in a midair collision while maneuvering at low altitude.
- [NTSB DFW08FA234](https://openairdocs.org/ntsb/DFW08FA234.md): Cessna E162 · Douglas, KS · Accident · No injuries · Field investigation · Final report · Sep 18, 2008 · N162XP · Substantial damage
  > The airplane's inability to recover from an intentional spin, despite proper control inputs by the flight test pilot. Contributing to the accident was the failure of the airplane's ballistic parachute system to properly deploy.
- [NTSB DEN08LA125](https://openairdocs.org/ntsb/DEN08LA125.md): Air Tractor AT-402B · Deerfield, KS · Accident · Minor injuries · Limited investigation · Final report · Jul 20, 2008 · N61318 · Destroyed
  > The pilot inadvertently stalling the airplane. Contributing factors in this accident were the pilot intentionally performing low altitude maneuvers (side slips), unporting and starving the engine of fuel, and his initiating a climb at low airspeed.

Next page: https://openairdocs.org/ntsb-phases/450/cases.md?state=KS&page=2

## The whole list in SQL

Runs in DuckDB 1.2 or later on the release's Parquet files over HTTPS:

```sql
WITH phase_names(main, name) AS (VALUES (100, 'Prior to flight'), (150, 'Standing'), (200, 'Pushback/towing'), (250, 'Taxi'), (300, 'Takeoff'), (350, 'Initial climb'), (400, 'Enroute'), (450, 'Maneuvering'), (500, 'Approach'), (550, 'Landing'), (600, 'Emergency descent'), (650, 'Uncontrolled descent'), (700, 'Post-impact'), (750, 'After landing'), (800, 'Other'), (990, 'Unknown')),
  crosswalk(code, main, name) AS (VALUES (500, 150, 'Standing'), (501, 150, 'Standing - pre-flight'), (502, 150, 'Standing - starting engine(s)'), (503, 150, 'Standing - engine(s) operating'), (504, 150, 'Standing - engine(s) not operating'), (505, 150, 'Standing - idling rotors'), (510, 250, 'Taxi'), (511, 200, 'Taxi - pushback/tow'), (512, 250, 'Taxi - to takeoff'), (513, 250, 'Taxi - from landing'), (514, 250, 'Taxi - aerial'), (520, 300, 'Takeoff'), (521, 300, 'Takeoff - roll/run'), (522, 350, 'Takeoff - initial climb'), (523, 300, 'Takeoff - aborted'), (530, 400, 'Climb'), (531, 400, 'Climb - to cruise'), (540, 400, 'Cruise'), (541, 400, 'Cruise - normal'), (542, 400, 'Maneuvering - holding (IFR)'), (550, 400, 'Descent'), (551, 400, 'Descent - normal'), (552, 600, 'Descent - emergency'), (553, 650, 'Descent - uncontrolled'), (560, 500, 'Approach'), (561, 500, 'Approach - VFR pattern - downwind'), (562, 500, 'Approach - VFR pattern - base turn'), (563, 500, 'Approach - VFR pattern - base leg/base to final'), (564, 500, 'Approach - VFR pattern - final approach'), (565, 500, 'Go-around (VFR)'), (566, 500, 'Approach - IAF to FAF/outer marker (IFR)'), (567, 500, 'Approach - FAF/outer marker to threshold (IFR)'), (568, 500, 'Circling (IFR)'), (569, 500, 'Missed approach (IFR)'), (570, 550, 'Landing'), (571, 550, 'Landing - flare/touchdown'), (572, 550, 'Landing - roll'), (573, 550, 'Landing - aborted'), (574, 550, 'Emergency landing'), (575, 550, 'Emergency landing after takeoff'), (576, 600, 'Emergency descent/landing'), (580, 450, 'Maneuvering'), (581, 450, 'Maneuvering - aerial application'), (582, 450, 'Maneuvering - turn to reverse direction'), (583, 450, 'Maneuvering - turn to landing area (emergency)'), (590, 450, 'Hover'), (591, 450, 'Hover - in ground effect'), (592, 450, 'Hover - out of ground effect'), (600, 800, 'Other'), (610, 990, 'Unknown')),
  current_codes AS (
    SELECT e.case_mkey, TRY_CAST(e."tier1Number" AS INTEGER) AS code,
      row_number() OVER (PARTITION BY e.case_mkey ORDER BY coalesce(e."isDefiningEvent", false) DESC, e.position) AS n
    FROM 'https://openairdocs.org/data/latest/ntsb_events.parquet' e
    WHERE e.aircrafts_position = 1 AND e."tier1Number" GLOB '[1-9][0-9]*'
      AND (e."isDefiningEvent" OR e.case_mkey IN (SELECT "mKey" FROM 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' WHERE "isPre1982"))
  ),
  phases AS (
    SELECT case_mkey, 'current' AS scheme, code, CASE WHEN code >= 990 THEN 990 ELSE code // 50 * 50 END AS main
    FROM current_codes WHERE n = 1
    UNION ALL
    SELECT o.case_mkey, 'older', o."phaseOfFlightCode", w.main
    FROM 'https://openairdocs.org/data/latest/ntsb_occurrences.parquet' o JOIN crosswalk w ON w.code = o."phaseOfFlightCode"
    WHERE o.aircrafts_position = 1 AND o."occurrenceNumber" = 1 AND o.case_mkey NOT IN (SELECT case_mkey FROM current_codes)
  ),
  case_phases AS (
    SELECT p.*, c."eventDate", c."highestInjuryLevel" = 'Fatal' AS fatal, a.aircraft_model_code
    FROM phases p JOIN 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c ON c."mKey" = p.case_mkey
    LEFT JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = p.case_mkey AND a.position = 1
    WHERE c."eventDate" >= DATE '1962-01-01' AND p.main IN (SELECT main FROM phase_names)
  )
SELECT c."ntsbNumber", c."eventDate", c."eventType", c."eventCity", c."eventStateOrRegion", a.n_number, a."aircraftMake", a."aircraftModel", c."highestInjuryLevel", c."totalFatal", c."completionStatus", c.report_url
FROM 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c LEFT JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = c."mKey" AND a.position = 1
WHERE c."eventStateOrRegion" = 'KS' AND c."eventCountry" = 'USA'
  AND c."mKey" IN (SELECT case_mkey FROM case_phases WHERE main = 450)
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb-phases/450/cases?state=KS

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.
